This invention relates to downhole transmission systems. U.S. Pat. No. 6,670,880, which is herein incorporated by reference, discloses a downhole transmission system through a string of downhole components. A first data transmission element is located in one end of each downhole component, which includes a first magnetically-conductive, electrically-insulating trough, and a first electrically conductive coil lying there in. A second data transmission element is located in the other end, with a similar arrangement comprising a second magnetically-conductive, electrically-insulating trough and a second electrically conductive coil. The transmission system further comprises an electrical conductor in electrical communication with and running between each first and second coil in the downhole component. The string of downhole components is cooperatively arranged such that the troughs are in magnetic communication with each other and transmit signals through induction. Each downhole component comprises electrical characteristics such as impedance, reactance, capacitance and inductance.
U.S. Pat. No. 4,914,433 discloses an improved electrical transmission system for transmitting electrical power and data signals within a well bore having a string of tubular members suspended within it, each tubular member having a receiving end adapted for receiving data signals and a transmitting end for transmitting signals. The receiving end and transmitting end being electrically coupled by a flexible printed planar conductor of the type having at least one substantially planar conductive band disposed between at least two layers of electrically insulating material.
It should be noted that the term “magnetically-conducting, electrically-insulating material” will be referred to in the rest of this specification as MCEI material.